Abstract The study deals with aspects of the population dynamics in the thornback ray (Raja clavata L., 1758), one of the most abundant cartilaginous fish caught in the North Aegean Sea. Females accounted for 73.08% and males 26.92% of all individuals. Total length of females and males ranged between 50.2 and 89.9 cm (disc width: 33.4–62.0 cm), and between 43.1 cm and 82.7 cm (disc width: 30.7–64.2 cm), respectively. Relationships between total length (TL) and total weight (TW), and between disc width (DW) and total weight (TW) were described by the equations: TW = 0.0041 TL3.10 and TW = 0.0178 DW3.03, respectively. Age data derived from vertebrae readings were used to estimate growth parameters using the von Bertalanffy function: L∞ = 101.71 cm, K = 0.18 y−1, t0 = −0.07 y for males and L∞ = 106.54 cm, K = 0.16 y−1, t0 = −0.28 y for females. The maximum age was 8 years for males and females. Total length at first maturity of males and females was 70.9 cm and 81.2 cm, respectively. Based on the gonadosomatic index and gonadal macroscopic observations, it was determined that the spawning period lasted throughout the year. Stomach content analysis showed that crustaceans (53.03% IRI) and teleosts (14.70% IRI) were the most preferred prey.

中文翻译：

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北爱琴海刺背鳐（Raja clavata Linnaeus, 1758）的生物学

摘要 该研究涉及刺背鳐 (Raja clavata L., 1758) 种群动态的各个方面，它是北爱琴海捕获的最丰富的软骨鱼之一。女性占73.08%，男性占26.92%。雌性和雄性的总长度分别在 50.2 和 89.9 厘米（盘宽：33.4-62.0 厘米）和 43.1 厘米和 82.7 厘米（盘宽：30.7-64.2 厘米）之间。总长度 (TL) 和总重量 (TW) 之间以及圆盘宽度 (DW) 和总重量 (TW) 之间的关系由以下等式描述：TW = 0.0041 TL3.10 和 TW = 0.0178 DW3.03，分别。来自椎骨读数的年龄数据用于使用 von Bertalanffy 函数估计生长参数：L∞ = 101.71 cm，K = 0.18 y−1，t0 = -0.07 y（男性）和 L∞ = 106.54 cm，K = 0.16 y− 1，t0 = -0。女性 28 岁。男性和女性的最大年龄为 8 岁。雄性和雌性初熟总长度分别为70.9厘米和81.2厘米。根据性腺指标和性腺宏观观察，确定产卵期为全年。胃含量分析表明，甲壳类动物（53.03% IRI）和硬骨鱼（14.70% IRI）是最优选的猎物。